In numerous areas of life hearing aid wearers can resort to what are known as pocket hearing aids. This is useful for example on training courses but also for the use of mobile telephones, stereo equipment and comparable media.
With a pocket hearing aid the microphone device including the signal processing is constructively separate from the earpiece. A device which can be carried in the breast pocket for example receives the audio signals, processes them and directs them over an appropriate cable connection to an earpiece which the hearing aid wearer wears in a/on their ear.
The output signals of training devices, mobile telephones, stereo systems and such like are provided for example through Euro jack plugs. The pocket hearing aid possesses an audio shoe which serves as an adapter for the hearing aid. The audio signals are transmitted from the relevant device output over a standard cable to the audio shoe of the hearing aid.
In addition it is known from publication U.S. Pat. No. 5,721,783 that wireless transmission of signals from an external device to a hearing aid is possible. These types of external devices, which can be referred to as RPUs (remote processor unit), can be produced for example in the form of a wristwatch or a piece of jewelry.
Utility model DE 203 03 190 U1 further discloses a handsfree device for hearing aids to allow hearing aid wearers to use mobile telephones, digital telephones and CD players. Here a support element of a behind-the-ear hearing aid features a coil which is connected by means of a lead via a microphone to a plug for direct connection to the devices to be used.
The further publication DE 35 08 830 A1 describes a hearing aid in which the earpiece is located outside the hearing aid housing in an otoplastic. The connection between an amplifier of the hearing aid and the earpiece is a wireless connection.